A computer company advertises its computers in PC World, in PC Magazine, and on television. A survey of 730 customers finds that the numbers of customers who are familiar with the company's computers because of the different forms of advertising are as follows:
306, PC World
240, PC Magazine
380, television
110, PC World and PC Magazine
135, PC Magazine and television
160, PC World and television
83, all three sources
How many of the surveyed customers know about the computers because of EXACTLY ONE of these forms of advertising?
customers